SP-A and SP-D enhance bacterial clearance and inhibit bacterial growth. SP-A and SP-D are oligomeric proteins synthesized by type II pulmonary epithelial cells and secreted in the liquid that covers the lung epithelium. Both SP-A and SP-D opsonize pathogens and enhance their phagocytosis by innate immune cells such as alveolar macrophages and neutrophils. In this issue of the JCI, Wu and coworkers provide compelling evidence that SP-A and SP-D also are directly bactericidal (1); they damage the bacterial cell membrane and inhibit bacterial growth. Thus, SP-A and SP-D enhance bacterial clearance via enhancing phagocytosis and via direct antimicrobial effects on bacteria. Images are not to scale.